Automatic cocking device in a crossbow for hunting and archery

ABSTRACT

A crossbow ( 1 ) includes a frame ( 2 ) having at least a flexing element ( 3 ) and a bowstring ( 4 ) strung between opposite ends of the flexing element ( 3 ) positioned substantially perpendicular, under rest conditions, to the shooting axis of the crossbow. On the frame ( 2 ) is mounted a trigger block ( 8 ) provided with means for catching and releasing the bowstring. The trigger block ( 8 ) can be translated on a rectilinear path parallel to the longitudinal axis of the crosssbow, in which in a first phase the trigger block advances towards the flexing element ( 3 ) until it automatically catches the bowstring ( 4 ), and in a second phase the trigger block ( 8 ) moves back until reaching a positioning of correct tensioning of the bowstring. The trigger block is actuated by electromechanical means shaped in such a way as to produce on the trigger block ( 8 ) a force that is substantially parallel to the shooting axis of the crossbow to carry out said first and second phase.

TECHNICAL FIELD AND BACKGROUND ART

The present invention relates to an automatic cocking device in acrossbow for hunting and/or archery.

In known archery and hunting crossbows, one of the main problems is thatof their cocking because of the considerable force required to tensionthe bowstring.

Crossbows are known in which cocking is facilitated by the presence of aring in the frontal area of the crossbows into which the shooter insertsa foot, so that with the crossbow bearing on the ground and secured byhis/her foot, the shooter can pull the bowstring towards him/her withhis/her hands until bringing it in the position in which it catches theshooting device associated to the trigger.

However, such a solution is still not very practical and it requiresconsiderable effort on the shooter's part: in fact crossbows withtensioning exceeding 150-180 pounds (corresponding roughly to 68-82 kg)cannot be constructed.

Another manual cocking system, already used in medieval times, comprisesa crank to be operated by the shooter to tension the bowstring by meansof reducing mechanisms, but such a solution is operatively complex andthe lesser effort required is paid for with an excessively long cockingtime.

Moreover, from U.S. Pat. No. 2,520,713 a crossbow is known in which thetrigger assembly can translate along the longitudial axis of thecrossbow. In a first phase the trigger assembly translates towards theflexing elements to catch the bowstring and in a second phase theoperator tensions the bowstring, returning the trigger device to therear position.

The cocking action therefore takes place manually, acting on the triggerassembly instead of directly on the spring.

Thus, such a crossbow has the drawbacks of a manually cocked crossbowespecially as regards the efforts the operator must exert during thecocking phase.

The sole automatic system known to the Applicant is the one disclosed inU.S. Pat. No. 5,220,906 which relates to a device to draw the bowstringof a crossbow, operated by a battery-powered electric motor and housedin a case associated in removable fashion to the crossbow.

The device comprises a shaft which is at least partly threaded and whichtranslates relative to the case on a guide and support walls, actuatedby the electric motor.

The electric motor sets in rotation (clockwise or counter-clockwisedepending on the position of a switch) a drive shaft whereon is keyed afirst gear wheel which meshes onto a second gear wheel mounted on asleeve having an inner thread which couples with the outer thread of thethreaded shaft that translates relative to the sleeve in such a way asto transform the rotational motion of the drive shaft into translatingmotion of the threaded shaft relative to the trigger of the crossbow.End stop sensors are provided to check the run of the threaded shaft.

However, this solution, which is the only one described in the patent,provides for the rather bulky housing that contains the motor and thebattery to be located in the front area of the crossbow in front of theshooting area, in a rather inconvenient position and which, in any case,requires the housing to be removed prior to shooting, both because ofthe impossibility of releasing the arrow and because the weight of thedevice on the tip of the crossbow would create an imbalance which wouldprevent the shooter from shouldering it correctly and from aimingproperly.

The patent also mentions the possibility for the device to be positionedin the rear area where the crossbow is shouldered, but it fails toexplain in any way how to position it, probably because the inventor didnot know how to position it to obtain an effective operation.

Indeed, if the device where actually to be located in the rear part ofthe crossbow it would have to pull the bowstring (instead of pushing it)during the cocking phase, but the element destined to interact with thebowstring (the slots 74 of the patent) is wholly unsuitable for grippingthe bowstring to pull it, as it can only push it.

Moreover, with all traditional bulky elements of the rear part of thecrossbow, it is difficult to comprehend a possible installation positionof the device which, among other problems, would act in a manner that isnot parallel to the shooting axis (as is readily apparent also from FIG.4 of the aforesaid document).

The lack of parallelism between the action of the automatic device andthe shooting axis of the crossbow is a further drawback of the crossbowdescribed in the aforesaid patent and it leads to the followingconsequences. If the device is mounted anteriorly, it produces a highlevel of friction of the bowstring against the frame of the crossbow andin particular against the plane whereon the arrow slides during thethrusting phase of the bowstring towards the trigger, whilst if thedevice is mounted posteriorly it cannot function because it would liftthe bowstring relative to the plane of shooting and hence the bowstringcould not be properly secured to the trigger.

Although the patent only describes the solution with the removablecocking device (which penalises the shooter who has to mount and removethe device every time he/she shoots), the patent also mentions thepossibility for the device to be permanently fastened to the crossbow,but fails to explain how this would be possible and where the devicewould be fastened. The reason for the many gaps in the patent should besought in the fact that the inventor probably had thought about somepossible variations but without finding any possible embodiment for themand hence without putting a person versed in the art in the condition toconstruct and embody such variations.

In particular, the aforesaid patent fails to teach how to fasten thedevice in a permanent manner without influencing the balance of thecrossbow and consequently penalising the shooting phase.

In effect, the solution described and illustrated in the patent isineffective and not feasible for the many problems described above, andin fact as far as the Applicant knows such a solution has never beenapplied commercially, whilst the other solutions only partiallymentioned but not illustrated or fully described (which, a fortiorl,have found no commercial application) do not constitute, in theApplicant's opinion, prior art.

To the aforesaid drawback one should add the fact that the cockingaction is effected directly on the bowstring, thus needing anappropriate fork element destined to interact therewith. This drawbackcould be overcome by applying to U.S. Pat. No. 5,220,906 the teachingsof U.S. Pat. No. 2,520,713, i.e. by having the electric motor actdirectly on a movable trigger. Such a solution would retain theaforementioned drawbacks, in particular because there would still be alack of parallelism between the action of the automatic device and theshooting axis of the bowstring, with the aforementioned consequences.

A manually and operable system for cocking the bowstring of a crossbowis disclosed by U.S. Pat. No. 5,823,172, wherein a mechanically operateddevice for drawing a bowstring with an uniform tension on either side ofthe crossbow stock is described.

However, such a device has the same drawbacks afore-mentioned about theautomatic system disclosed by U.S. Pat. No. 5,220,906.

In particular the cocking device is not an electromechanical automaticcocking device, acts on the bowstring through an inclined fork which canonly push and not pull the bowstring and so the device has to be placedon the front edge of the crossbow and has to be removed before shooting.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to eliminate the aforesaid drawbacksand to make available a device for automatically cocking a crossbowapplicable to the crosssbow itself in a fixed manner, with no need toremove it every time one shoots.

Another aim is to avoid frictions and jams during the crossbow cockingphase.

A further aim to achieve the above in a simple and reliable manner,without increasing the length or generally the dimensions of thecrossbow itself thus avoiding imbalances which would adversely effectthe shooting phase.

Said aims are fully achieved by the device of the present inventionwhich is characterised by the content of the claims set out below and inparticular in that the trigger block can translate on rectilinear pathparallel to the longitudinal axis of the crossbow, in which in a firstphase the trigger block advances towards the flexing element until themeans for catching and releasing the bowstring automatically catch thebowstring, and in a second phase the trigger block moves back untilreaching a position of correct tensioning of the bowstring in which theoperation of the trigger causes the instantaneous release of thebowstring, and in that it comprises electromechanical means so shaped asto produce on the trigger block a force substantially parallel to theshooting axis of the crossbow to carry out said first and second phase.

The electromechanical means for automatically tensioning the bowstringcomprise an electric motor anchored underneath the crossbow in the areabetween the trigger block and the butt and powered by a batterypreferably housed at the rear part of the crossbow frame or at a grip ofthe crossbow itself.

The electromechanical means preferably comprise a ball screw whoselow-friction rotation causes the movement of a sleeve associated withthe trigger block by means of a draw wire sliding on pulleys.

The crossbow can also be provided with a flexing element divided intotwo halves, each pivotally engaged to the crossbow with the ability torotate relative thereto in order to be easily made operative bytensioning the bowstring.

BRIEF DESCRIPTION OF THE DRAWINGS

This and other features shall become more readily apparent in thefollowing description of a preferred embodiment illustrated, purely byway of non limiting example, in the accompanying drawing tables, inwhich:

FIG. 1 shows a partially sectioned lateral view of the crossbow;

FIG. 2 shows a partially sectioned top view of the crossbow of FIG. 1;

FIG. 3 shows a partially sectioned lateral view of the crossbow of FIG.1;

FIG. 4 shows a first view of the crossbow of FIG. 1;

FIG. 5 shows a detail of the crossbow of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the figures, the number 1 globally refers to a huntingcrossbow (though it could also be an archery crossbow) which in somefigures is shown without its covering fairing, the better to highlightits internal components.

The crossbow 1 comprises a frame 2 which extends longitudinally and endsfrontally with a flexing element 3 for tensioning a bowstring 4, whilstin the rear part it is provided with a butt 5 for the correctpositioning of the crossbow by the shooter.

The frame 2 further comprises two grips 6 and 38 which extendsinferiorly from the frame itself to allow the shooter to sustain andoperate the crossbow 1.

As the figures show, the distance between the grip 6 and the butt 5 issmaller than, and in particular equal to about 0.5-0.8 times, thedistance between the grip 6 and the front end of the crossbow. Thissolution makes the crossbow extremely compact and easy to handle.Moreover the frame 2 comprises in the front part two longitudinal andparallel guides 7, whereon slides a trigger block 8 provided with meansfor catching and releasing the bowstring of a substantially known kindand hence not described in detail herein.

In this way the trigger block 8 can originally translate on arectilinear path, parallel to the shooting axis of the crossbow, inwhich during a first phase the trigger block advances towards theflexing element 3 until the means for catching and releasing thebowstring automatically catch the bowstring 4, and in a second phase thetrigger block 8 moves back until reaching a position of correcttensioning of the bowstring in which the operation of the trigger causesthe bowstring to be released instantaneously.

The guides 7 are obtained by means of mutually parallel tension rods andare fastened anteriorly to a support 9, which also sustains the flexingelements, and posteriorly to a plate 10 comprised in the frame 2 and inparticular in the portion that embodies the butt 5.

An electric motor 11 and a battery 12 are associated to the crossbow andsubstantially incorporated therein. In particular the butt 5 internallyhouses the electric motor, whilst the battery 12 can advantageously beinserted in the grip 6 of the crossbow. The battery 12 therefore isanchored in removable fashion by means of a pushbutton 39.

The operation of the electric motor causes the rotation of a drive shaft13 whereon is keyed a first pulley 14 which through a transmission belt15 sets in rotation a second pulley 16 keyed onto the end of a ballscrew 17 housed between the support 9 and the plate 10, parallel andsuperiorly relative to the shooting axis or longitudinal axis of thecrossbow. In particular the ball screw is positioned centrally relativeto the longitudinal axis of the crossbow, in such a way as not to affectthe stability of the crossbow, especially when shooting.

The ball screw 17 is a known device, essentially comprising a worm screwwhereon slides a cylindrical sleeve 18 internally provided with ballsthat interact with the thread of the screw, allowing 95% efficiency interms of friction.

As shown in the figure, the ball screw 17 is inserted in two bellows 19,respectively introduced between the support 9 and the sleeve 18 andbetween the sleeve 18 and the plate 10, to protect moving parts.

The sleeve 18 is connected to the trigger block 8 in such a way that,when the electric motor causes the rotation of the ball screw, thesleeve 18 translates thereon causing a corresponding translation, ofequal extent, of the trigger block 8.

The ball screw 17 also has two shock absorbing elements 20 to brake therun of the sleeve and operate a spring clutch comprised in a springassembly 26. Said shock absorbing elements can be embodied by helicalsprings or rubber elements.

The electric motor 11 with the ball screw 17 and the sleeve 18constitute electromechanical means for the automatic tensioning of thebowstring, originally shaped in such a way as to produce, on the triggerblock 8, a force that is substantially parallel to the longitudinal orshooting axis of the crossbow.

For this purpose the electromechanical means further comprise a drivingelement intregal the trigger block, obtained by means of two draw wires21 actuated by the electric motor. The two draw wires 21 are positionedon the sides of the ball screw 17 and each of them has both its endsintegral with the trigger block 8.

The draw wire 21 is integral, in its intermediate position, with thesleeve 18 and slides on pulleys 22 mounted able to rotate on the frame 2from opposite sides along the run of the trigger block 8.

The presence of the draw wires 21, able to slide on the pulleys 22,guarantees the action of a force substantially parallel to thelongitudinal or shooting axis of the crossbow, together with the actionexerted by the ball screw 17, by the sleeve 18, able to slide on theball screw 17 and by the guides 7.

For the operation of the electric motor 11, an electronic speed controlunit, indicated with 23, is provided together with a control 24 todetermine the direction of rotation of the motor (and hence oftranslation of the trigger assembly). The speed control unit 23 and thecontrol 24 can be applied to the grip 6, as shown in FIG. 1.

The electric motor 11 is also provided with an epicyclical reductiongear 25 and with the clutch assembly 26 interposed between the electricmotor and the first pulley 14.

The trigger block 8 is of a substantially known type (apart from theability to translate) and comprises an actual trigger 27 pivotallyengaged on the trigger assembly 8 by means of a bearing and operativelyassociated to a catch 28 to hold the bowstring 4. Associated to thetrigger assembly 8 is further provided a safety device 29, comprising abreech bolt 30 and a safety lever 31.

As shown in the figure, the flexing element can be subdivided in twohalves 3 a each of which is pivotally engaged in 32 to the crossbow.Each half is shaped as to be able to rotate relative to the frame 2 toshift from a rest position, in which the two halves are substantiallyparallel to the frame, to a working position, in which the two halvesextend transversely relative to the frame to tension the bowstring, andvice versa.

In particular, means 33 for locking and tensioning the bowstring areprovided with the purpose of tensioning the bowstring 4. Said meanscomprise two pivot pins 34 having a first end integral with the frame ofthe bowstring and able to be inserted into a slot 35 obtained in each ofthe two halves in proximity to the end pivotally engaged to the frame.The locking action is effected by means of threaded elements 36 able tobe operatively associated to the pivot pins, by the interposition of anelement 37, at least partially cylindrical, to facilitate the placementof the halves in the working position.

According to an embodiment variation not shown herein, the flexingelement can be single and fastened to the crossbow. In this case, aprovisional exterior string is used, tensioning which the flexingelement is bent until the actual string can be inserted, according to aknown technology.

As regards the positioning of the device, when the bowstring is to betensioned acting on the flexing element 3, it is necessary to insert thepivot pins 34 in the respective slots 35 and to screw the threadedelements 36 by approaching the two parts of the flexing element to thesupport 9. The presence of the element 37 reduces friction andfacilitates the locking of the flexing element.

When it is necessary to cock the crossbow again after releasing anarrow, it is sufficient to act on the pushbutton for the operation ofthe electric motor to cause the trigger block to advance towards thebowstring.

Before the trigger block reaches the aforesaid end stop, the bowstringis automatically engaged in its catching device comprises in the triggerblock, automatically engaging the safety device that prevents accidentalreleases of the arrow.

By inverting the direction of motion of the motor, it is possible tocommand the adjustable tensioning of the bowstring, by returning thetrigger block in position. The sleeve 18 drives the draw wire 21 whichslides along the pulleys 22 and generates the translation of the triggerblock 8 until the tun of the sleeve is limited by the shock absorbingelements 20 and arrested by the clutch 26. The presence of the two drawwires positioned symmetrically relative to the axis of the crossbowguarantees a balanced, frictionless interaction between the triggerblock 8 and the respective guides 7 and exerts on the trigger block aforce parallel to the shooting axis of the crossbow.

The main advantages of the present device consist of the capability toshoot several times with no effort on the operator's part and of thecapability to load far greater powers than in current systems, in thecapability to uncock the weapon without necessarily shooting the arrow(it is sufficient to operate the electric motor as in the initial phaseto move the trigger block closer to the flexing element, therebyreducing the tension on the bowstring), in the availability of a cockingdevice incorporated in the crossbow itself and in such a position thatit does not hamper or hinder the operator in shooting operations.

In particular, unlike U.S. Pat. No. 5,220,906, no element is positionedin front of the flexing elements, and this allows for perfect balancingof the crossbow.

A further feature and advantage of the present automatic cocking deviceis given by the fact that it operates with a force that is parallel tothat of the arrow and therefore entails no jams or frictions during thecocking phase or modifications on the trajectory of the arrow during thelaunching phase.

The present device further allows for contacting of the bowstring alwaysin the same place and centrally, avoiding asymmetries.

What is claimed is:
 1. An automatic cocking device in a crossbow (1) forhunting and/or archery, of the type comprising: a frame (2) having atleast a flexing element (3) and a bowstring (4) strung between oppositeends of the flexing element (3) and positioned substantiallyperpendicular, under rest conditions, to a shooting axis of thecrossbow; electromechanical means for the automatic cocking of thebowstring (4), said electromechanical means comprising at least afeeding device and actuator means; a trigger block (8) provided withmeans for catching and releasing the bowstring; wherein said triggerblock (8) translates on a rectilinear path with a draw line coaxial tothe longitudinal axis of the crossbow, in which in a first phase thetrigger block advances towards the flexing element (3) until means forcatching and releasing the bowstring automatically catch the bowstring(4), and in a second phase the trigger block (8) moves back untilreaching a position of correct tensioning of the bowstring in whichoperation of the trigger causes instantaneous release of the bowstring,and wherein said electromechanical means are so shaped as to produce onthe trigger block (8) a force that is substantially coaxial to theshooting axis of the crossbow to carry out said first and second phase.2. A device as claimed in claim 1, wherein said electromechanical meanscomprise at least a drawing element integral with the trigger block (8)and actuated by the electromechanical means, the actuator means beingintegral with the crossbow and positioned in a manner that does notnecessitate removal thereof before shooting.
 3. A device as claimed inclaim 2, wherein the drawing element includes at least a draw wire (21)actuated by the electromechanical means and having at least an endintegral with the trigger block (8).
 4. A device as claimed in claim 3,wherein the draw wire (21) has both its ends integral with the triggerblock (8) and slides on rotating pulleys (22) mounted on the frame (2)at opposite sides along the run of the trigger block.
 5. A device asclaimed in any of the claims from 2 to 4, wherein said electromechanicalmeans comprise: a ball screw (17) positioned parallel to thelongitudinal axis of the crossbow and cinematically connected to anelectric motor (11) which causes its actuation; a sleeve (18), slidingon the ball screw towards the front part of the crossbow or towards itsrear part depending on the direction of rotation of the ball screws, andoperatively associated to the drawing element of the trigger block.
 6. Adevice as claimed in claim 5, wherein said ball screw (17) comprises ateach end a shock absorbing element (20) to brake the run of the sleeve(18) and operate a clutch assembly (26).
 7. A device as claimed in claim1, wherein the electromechanical means further comprise at least a guide(7) integral with the frame (2) of the crossbow parallel to thelongitudinal axis thereof, whereon the trigger block (8) slides.
 8. Adevice as claimed in claim 1, wherein the electromechanical meanscomprise: an electric motor (11) anchored in the area between thetrigger block (8) and a butt (5) or the rear part of the crossbow, and abattery (12) connected to the electric motor to power the same.
 9. Adevice as claimed in claim 8, wherein the battery (12) is anchored, in aremovable manner by a pushbutton (39), to a grip (6) integral with theframe (2) of the crossbow.
 10. A device as claimed in claim 8, whereinthe battery (12) is anchored, in a removable manner, to the rear part ofthe frame (2) of the crossbow between the trigger block (8) and the butt(5) or terminal part of the crossbow.
 11. A device as claimed in claim8, wherein the electromechanical means further comprise an epicyclicalreduction gear (25) associated with the electric motor (11).
 12. Adevice as claimed in claim 11, wherein the electromechanical meansfurther comprise a clutch assembly (26) associated with the electricmotor.
 13. A device as claimed in claim 1, wherein the flexing element(3) is divided in two halves (3 a), each of which is pivotally engagedto the frame (2) of the crossbow and so shaped as to be able to rotaterelative thereto in order to shift from a resting position, in which thetwo halves are substantially parallel to the frame, to a workingposition, in which the two halves extend transversely relative to theframe to tension the bowstring, and vice versa.
 14. A device as claimedin claim 13, wherein each of the halves (3 a) comprises means forlocking and tensioning (33) the bowstring, which operate to shift fromthe resting position to the working position.
 15. A device as claimed inclaim 14, wherein the locking and tensioning means (33) comprise: twopivot pins (34) having a first end integral with the frame (2) of thecrossbow; a slot (35) in each of the two halves in proximity to thefirst end pivotally engaged to the frame to receive said pivot pin (34);threaded elements (36) able to be operatively associated to said pivotpin (34) to lock the two halves (3 a) in the working position.
 16. Adevice as claimed in claim 15, wherein the locking and tensioning means(33) further comprise: an element (37) that is at least partiallycylindrical and inserted between one half (3 a) and the respectivethreaded element to facilitate positioning of the halves in the workingposition.
 17. A crossbow comprising a device according to claim
 1. 18. Acrossbow as claimed in claim 17, wherein the distance between a grip (6)and a butt (5) is lesser than the distance between the grip (6) and thefront end of the crossbow.
 19. A crossbow as claimed in claim 18,wherein the distance between a grip (6) and a butt (5) is lesser by afactor of 0.5-0.8 than the distance between the grip (6) and the frontend of the crossbow.
 20. A crossbow as claimed in claim 17, wherein noelement is applied to the front end of the crossbow.
 21. A crossbow asclaimed in claim 17, wherein the device further comprises an electricmotor (11), an epicyclical reduction gear (25), and a clutch assembly(26), all of which are positioned in the rear part of the crossbow. 22.A crossbow as claimed in claim 17, wherein the device further comprisesa ball screw (17) positioned centrally parallel and superiorly relativeto the shooting axis or longitudinal axis of the crossbow.
 23. Acrossbow as claimed in claim 17, wherein the electromechanical meansallow uncocking of the crossbow without necessarily shooting an arrow.